The present invention relates to an intermittent motion drive assembly for converting continuous rotary motion of an input drive member to intermittent rotary output motion of an output member.
Motion converting drive assemblies are well known and have been produced with varying degrees of complexity using cams, gears, levers and the like. For use in driving webs for transporting articles from point to point, for example, there is a need for an intermittent drive assembly that is free from first and second derivative discontinuities whereby smooth acceleration and deceleration is obtained from and to zero velocity movement.
In my U.S. Pat. No. 5,080,636, issued Jan. 14, 1992, there is described and claimed an intermittent motion drive assembly capable of providing the aforementioned desired operation. In the drive assembly described therein, a cylindrical member driven by a planetary gear arrangement traverses an epitrochoid path to periodically enter a radial slot in an arm or disc rotating the arm or disc through 180.degree.. By selecting the parameters appropriately the cylindrical member is caused to enter and leave the radial slot along a tangential path such that no first or second derivative discontinuities are present in the motion of the arm or disc. Several embodiments are disclosed for achieving either one or two incremental rotations of an output shaft for a single revolution of an input shaft.
In attempting to adapt the drive assembly to various uses, a need has arisen to provide for speed reduction with concomitant increase in power delivering capability. Ideally, the improved ability should be obtained without requiring an increase in envelope size of the assembly.